A major goal of primary care is to prevent the morbidity and mortality associated with common chronic diseases such as hypertension, type 2 diabetes, and hyperlipidemia. However, national and local data indicate that we are falling well short of evidence-based goals for these three conditions, both in terms of risk factor control and of monitoring for associated adverse drug events (ADEs). Although there are many contributors to sub-optimal care, lack of timely medication intensification and safety monitoring among patients with elevated risk factor levels has been identified as a prevalent and potentially modifiable barrier to effective and safe chronic disease care. Our current primary care system is based to a large extent on a model of episodic, visit-based care for acute complaints that is not well-suited for longitudinal chronic disease management, particularly for conditions that require medication initiation, monitoring, and iterative dose titration to achieve risk factor control. As the U.S. health care system begins the transition to electronic health records (EHRs), advances in health information technology (IT) now offer the opportunity to develop and rigorously evaluate new models of primary care. We propose to test a model of chronic disease medication management in which the decision to initiate or adjust medical therapy is directly linked to a sequence of subsequent, clinical actions (e.g. monitoring for ADEs, assessing response to therapy, changing medication dose) performed independently of the office visit. We hypothesize that establishing a visit-independent, health IT-supported cycle of laboratory monitoring and iterative medication dose adjustment will result in more effective chronic disease care. To implement this model, we will build on our existing EHR and integrated data systems to develop an advanced health IT application called the "Medication Metronome" to track laboratory test due dates and results, report results to both patients and providers, and facilitate between-visit medication dose adjustment by providers. The choices of interval and evaluation modality will be tailored by the provider to optimize individual care decisions. The goal of this intervention is to develop an efficient system to ensure that patients are rapidly and safely brought to evidence-based treatment goals and to prevent delays in planned laboratory monitoring by eliminating the requirement for an office visit. The broader goal of this work is to foster greater patient-physician connectedness by combining visit- independent medication management with more productive visit-based care. Novel uses of health information technology (IT) are needed to support more effective medication management for chronic diseases in the primary care setting. This study will evaluate in a controlled trial the value of an IT system that supports between-visit medication safety monitoring and dose adjustment. This research is relevant to nationwide efforts to rigorously demonstrate the most effective ways to implement new IT-based delivery models that expand care beyond the traditional clinic visit.